Processes and devices for preparing toner composition and pre-toner mixtures used in toner compositions are known. For example, processes for preparing toner compositions are generally disclosed in U.S. Pat. No. 4,883,736 to Hoffend et al. and U.S. Pat. No. 7,459,258 to Chung et al., the disclosures of which are totally incorporated herein by reference. Examples of commercially known processes may include melt blending of pre-toner mixtures in a twin screw extruder compounder (available from Corperion Corporation, Ramsey, N.J.) and in a dispersion of pigment and wax in aqueous phase in a batch stirred tank.
Batch processes may be used for preparing chemical toners in an aqueous phase, which involves a high temperature emulsification of molten wax stirred in a vessel followed by homogenization in a homogenizer, such as for example, a Gaulin homogenizer.
Batch processes require long processing times and consume a great deal of energy. Multiple passes through the homogenizer may be required to obtain a desired level of emulsion and to ensure uniformity and size of the toner particle prepared using batch processes. However, even after multiple passes, obtaining a desired level of emulsion, uniformity, and size is not guaranteed. It is difficult to produce batch-to-batch consistency and scale-up the batches due to different batch reactions. Batch processes also require constant attention because an entire batch may have to be aborted if a batch process runs out of control in terms of temperature, impeller speed, and the like.
Therefore, there is a need for improved toner producing processes, that is, continuous aqueous chemical toner processes for preparing toner compositions. In addition, there is a need for processes that provide more control of the particles produced, including maintaining quality, uniformity, and size, without the extensive time and energy used in batch process methods.